114 H. JAMES-CLARK ON THE ANATOMY 



IV. The Anatomy and Physiology of the VorticeUidan Parasite (Trichodina pediculus, Ehr.) of 



Hydra. By Prof. H. James-Clark, A. B., B. S. 



Read October 18th, 1865. 



1 HERE can be no doubt tbat a large amount of tbe diversity of opinion in regard to the 

 general and classificatory relations of animals arises from the lack of a correct knowledge 

 of the intimate structure of the subject under controversy. Tins is especially applicable to 



the lower forms of life, and above all to the fifth and lowest grand division of animals, the 



Protozoa. Theories which are based upon insufficient observations, and a misconception of 

 facts, not only present a distorted view of Nature, but mislead and give a wrono- direction 

 to the tendencies and currents of scientific research. The theory of the unicellular nature 

 of Infusoria — so acutely upheld by the arguments of Siebold and Kolliker, and especially 

 by the latter in his papers on the Gregarinidae * and on Actinophrys 2 — had no small 

 influence in blinding the mental vision of subsequent investigators ; and long delayed the 

 conclusion, strangely enough too, seemingly favored by Kolliker himself, that it is not 

 essential to the constitution of a cell that it should possess a tangible, distinctly differ- 

 entiated envelope. 



At the present day we may safely consider every one of the minutest centres of organic 

 development and action as so many individual cells, — not only potentially, but as essentially 



so as are any of the most decidedly wall-bound cells of the highest kind of tissue, and 



yet not become liable to the accusation of leaning toward a visionary method of investi- 

 gating or interpreting the phenomena of Nature. It really seems as if the much-abused 

 spirit of Oken is about to have its revenge, and the prophetic vision of that immortal genius 

 is soon to be realized by the eyes of the philosophers of the present day. Happily, among 

 the rising generation of the naturalists of this country, a growing independence of thought 

 and action — too long under the shade of the upas-tree of fictitious authority, and allured 

 by the deceitful and fascinating exterior of superficial, glittering, swift, and hasty generali- 

 zation — is leading to this result with rapid strides. 



Neither the genius of a Spencer nor the incomparable ingenuity and tact of a Tolles are 

 able to increase the availability of the microscope as rapidly as the requirements of scien- 

 tific progress demand ; and if one would see beyond the mere optical image of the instru- 

 ment, he should, by careful and judicious treatment, train the eye to develop to the 

 requirements of the occasion. It must become to him a sliding-scale of adjustable optical 

 powers. The tutored eye of Ehrenberg saw far more than the microscopes of his earlier 

 days could help him to discern. The truth of this is especially observable in the sur- 

 passing naturalness and life-like character of his illustrations, so often superior to the 

 delineations of his more modern compeers. When we have combined the effect of the 

 former with the more accurate details of the latter, we shall then, and not till then, have 

 arrived at an honest representation of animal life, and have laid a firm foundation for a 



1 Beitrage zur Kenntniss niederer Tkiere. Zeitsch. fur Actinophrys (A. Eichhornii) are " true cells with a distinct trail 

 Wiss. Zool., Bd. I. 1848-49, s. 1. a h out them" In a new work, {Mind in Nature; or, The Ori- 



2 Das Sonnenthierchen, Actinophrys sol. Zeitsch. fiir Wiss. gin of Life and the Mode of Development of Animals, New 

 Zool., Bd. I. 1848-49, s. 198. In some remarks upon Actin- York, 1805,) just issued from the press, I have reiterated this 

 oplirys, which I took occasion to make at a meeting of the statement, and given still further details of the anatomy and 

 Boston Society of Natural History, (see Proceedings for Sep- physiology of Actinophrys. 



tember 16, 1863,) I stated that the so-called vacuoles of the 



